A planned and started transfer to the decarbonized power grids is based first of all on increased use of the fossil fuels with reduced carbon content, such as natural gas in gaseous and liquefied states. In the latter case an implication of the LNGSR terminals is constantly growing. As described in “Handbook of Liquefied Natural Gas” (by Saeid Makhatab, et al., Elsevier, Oxford, 2014), they perform the unloading and storage of the imported liquefied natural gas (LNG) and its on-demand pumping, regasification and injection into transmission pipeline. According to report of the LNG-Worldwide Ltd. “Current Outlook for Global LNG to 2020 and European LNG Prospects” (September 2014), in 2013 the 104 existing LNGSR terminals in 29 countries have imported 237 MTPA of LNG fuel, providing at the time approximately 10% of the global gas consumption. Thereby, a volume of imported LNG is expected to grow by 2025 up to 500 MTPA.
Recently the floating storage and regasification units (FSRU) have been introduced in the LNG market. Moreover, the concepts of FSRU integrated with barge-mounted power plants (BMPP) are intensively now developed by the Wison, BWSC, TGE-Marine Gas Engineering, Samsung and Hyundai Heavy Industries and other companies. These near-shore Floating Storage, Regasification and Power production Units (FSRPU) may be the flexible and economic alternative to building the land-based LNG regasification terminals and stationary power plants, since they can avoid the long lead time and high cost of building the land-based facilities and offer quick deployment to a range of potential locations. Being connected to the local land-based electrical and gas networks they may provide the seasonal or intermittent deliveries to smaller and remoted gas and power customers with the significantly reduced CAPEX and OPEX indexes.
The developers of a FSRPU concept claim the benefit of recovering a high-grade waste heat from the power generators installed at the BMPP for regasification of LNG instead of using the air, sea water or intermediate carrier-based LNG evaporators for this purpose. However such technical solution does not make possible to use the mentioned waste heat for increase in fuel efficiency of power generation processes and does not obviate a need for use of the said LNG evaporators during operation of the power generators at low loads. In addition, dissipation of cold thermal energy of the LNG being regasified eliminates a possibility of its profitable use in the integrated energy conversion processes, contrary to proposed, for example, operation of the land-based LNGSR terminal in conjunction with the co-located Liquid Air Energy Storage (LAES) system (see the U.S. patent application Ser. No. 16/109,884). Here a cold thermal energy of LNG converted into cold thermal energy of liquid air is profitably used for reliquefying up to 35% of send-out natural gas during LAES facility discharge. What is more, availability of liquid air as an intermediate product of the LAEStechnology makes possible to gain the other benefits from its harnessing: provision of zero-carbon emitting exhaust of LAES facility through a cryogenic capture of CO2 component (as described in the published U.S. Patent Application No. US 20180221807) or an increase in power output and efficiency of the LAESfacility equipped with the semi-closed CO2 bottoming cycle (as described in the provisional U.S. Patent Application No. 62/554,053).
By this means there is a need for improvement in design of the FSRPU. A basis for such improvement could be an integration between the FSRPU and LAES into floating Liquid Air and Gas Energy Storage (LAGES) and elaboration of such method for its operation which would provide: a) full obviation of the need for usage of the air, sea water or intermediate carrier-based LNG evaporators; b) an effective recovery of high-grade waste heat from power generators for increase in its output and fuel efficiency; c) a further improvement in performance of the LAESsystem through reducing the energy intensity of air liquefaction; and d) widening the applicability of the LAGES system through an efficient its operation both in the load-following regime with energy storage capability and in base-load mode.